Consult /usr/share/doc/kernel-doc-2.6.18/Documentation (kernel-doc-2.6.18-164.el5 rpm) for more info on these parameters. The above mentioned Oracle document does a good job of explaining the parameters as well.

Although, I did not do any scientific measurements, just from the CPU usage live graph and pidstat (sysstat), I can confirm that my CPU usage dropped drastically.